TROPICAL FOREST BIODIVERSITY - DISTRIBUTIONAL PATTERNS AND THEIR CONSERVATIONAL SIGNIFICANCE

Phytogeographical knowledge of two major patterns important to conservational planning - the distribution of diversity and endemism in tropical forests - are summarized. High diversity forests occur on all three continents and are concentrated in lowland areas with high and evenly distributed rainfall, but with greatest diversity usually occurring in northwest South America forests. Tree and liana species richness is greatest in upper Amazone and non-tree species richness greatest in the northern Andean foothills and southern Central America, suggesting conservational priority for these areas. Endemism is only partly correlated with diversity and is concentrated in isolated patches of unusual habitat, in cloud forests, in topographically dissected montane areas, and on continental fragment islands, areas which also deserve conservational priority. Since different taxa show different distributional patterns, herbs and epiphytes, as well as trees and large vertebrates, must be considered in tropical conservational planning.